Seven-Coordinate Tb Complexes with 90% Quantum Yields: High-Performance Examples of Combined Singlet- and Triplet-to-Tb Energy-Transfer Pathways.

Seven-coordinate, pentagonal-bipyramidal (PBP) complexes [Ln(bbpen)Cl] and [Ln(bbppn)Cl], in which Ln = Tb (products and ), Eu ( and ), and Gd ( and ), with bbpen = ,'-bis(2-oxidobenzyl)-,'-bis(pyridin-2-ylmethyl)ethylenediamine and bbppn = ,'-bis(2-oxidobenzyl)-,'-bis(pyridin-2-ylmethyl)-1,2-propanediamine, were synthesized and characterized by single-crystal X-ray diffraction analysis, alternating-current magnetic susceptibility measurements, and photoluminescence (steady-state and time-resolved) spectroscopy. Under a static magnetic field of 0.1 T, the Tb complexes and revealed single-ion-magnet behavior.